Jump to content
Sign in to follow this  

Lambda values on a 2 stroke..

Recommended Posts

I was thinking about putting a lambda sensor in my header and buy a simple display to show the value to see how good/bad my jetting is. Bike is 2 stroke 300 ktm btw. But iam not sure what numbers to aim for?

Share this post


Link to post
Share on other sites

12.8

However... the oils in a 2S will kill the sensor in probably 30 minutes. Hence very few people use one in a 2S (and then, only in dyno runs). If compelled, be sure to use a five wire wide band.

Share this post


Link to post
Share on other sites

You can run an O2 in a 2 stroke a lot longer if you have it out of the direct exhaust stream. A few places making widebands sell adaptors that basically just space the sensor back an inch or so. Response time suffers, but for steady-state conditions that doesn't matter. Still won't last as long as a 4 stroke application, but might change that 30 minutes to a hundred hours. Run conditions, oil mix ratio, etc etc will all effect life.

Share this post


Link to post
Share on other sites

14.7:1 is stoichiometric, but you will make the most power in the 12.5-13:1 range.

Amsoil makes a 2 stroke oil that claims it can be run at 130:1 in racing applications. I would use that to keep the sensor functioning.

Share this post


Link to post
Share on other sites

12.8

However... the oils in a 2S will kill the sensor in probably 30 minutes. Hence very few people use one in a 2S (and then, only in dyno runs). If compelled, be sure to use a five wire wide band.

not true, we run wide-band afrs in turbo 2 stroke sleds for thousands of km each season no problems. running 25:1 with dominator, (injection pump deleted so its premix, save about 10 lbs) heat kills them though. using an extended bung with cooling fins help keep them alive.

A afr bung just after the pipe and just befor the silencer could work really well. gauge mounting would be a pain in the arse. and u would have to power it. Tuning by egt would work as well. 1250 max with a egt probe in the neck of the pipe as close to the piston crown as possible.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×